Stainless Steel Cookware Terms, Decoded

Photo of a stainless steel cookware setmiflippo /Depositphotos

Many home cooks choose stainless steel cookware because it can be used to cook just about anything, can go on the stove or in the oven, and can safely be cleaned in the dishwasher.

Add to that the fact that there’s no non-stick coating to scratch or no cast-iron seasoning to flake off, and stainless steel pans and pots easily win the title of the easiest cooking vessels to care for in your cabinets.

If you’re thinking of equipping your kitchen with stainless steel cookware, by now, you’ve probably seen just how confusing manufacturers’ product descriptions can get for first-time buyers!

So, in this post, I will help you decode all of the terms that you need to know before you can make the right choice for you, like 18/10 steel, tri-ply construction, and others.

For your convenience, I’ll do this in a Q&A format. If you came here, but couldn’t find your question, ask away the comments form below this post! I’ll do my best to answer within a day or two.

Table of Contents

What Is Food-Grade Stainless Steel?

Stainless steel is a metal alloy—a material made by combining two or more metals together—that consists of iron, carbon, at least 11% chromium, and nickel.

Food-grade stainless steel is designed for use in the harsh conditions of a professional or home kitchen, where it’s exposed to heat, water, acidic foods, and cleaning chemicals multiple times a day.

Why Does Stainless Steel Have Carbon In It?

Iron is a soft metal, so carbon is added to give it strength and toughness. 

But you can’t add too much carbon to stainless steel because it will start to corrode and rust easily. So the alloy used for making stainless steel cooking vessels typically contains between 0.03% and 0.8% carbon.

Skillets and pots made of metal with a higher carbon content are considered to be made of carbon steel, and not stainless steel (more on that below).

Is Stainless Steel the Same as Carbon Steel?

Stainless steel is not the same material as carbon steel, and the two shouldn’t be confused. The former has a carbon content no higher than 0.8%, while the latter can contain as much as 2% carbon.

Stainless steel cookware is oven-safe at temperatures of up to 600°F, whereas carbon steel can be heated to as high as 800-1,200°F depending on the make and model.

Carbon steel can be seasoned and develops a natural coating with non-stick properties over time, so it requires fewer fats and oils than stainless steel. However, it’s also prone to corrosion and rust, so it can only be cleaned by hand.

Why Does Stainless Steel Contain Chromium and Nickel?

Stainless steel gets its name from the fact that the chromium content in the alloy protects the iron from corrosion and the nickel content defends it from rust. They also give the cooking surface its distinct metallic shine.

The difference between corrosion and rust, for readers who may be wondering, is that all metals corrode, but only some metals rust.

Corrosion is when a metal degrades over time as it comes into contact with the oxygen in the air. Rust is a form of corrosion that only happens to metals containing iron. It requires the presence of oxygen and moisture.

As a rule of thumb, a higher concentration of chromium and nickel in the steel alloy gives your pans and pots greater protection against corrosion and rust, which means they’ll last longer. But it also makes them more expensive.

What Does 18/10, 18/8, and 18/0 Stainless Steel Mean?

Manufacturers use fractions, like 18/10, 18/8, and 18/0, to indicate the amount of chromium and nickel contained in their alloys. The first number tells you the amount of chromium; the second the amount of nickel.

For example, a frying pan made of 18/10 stainless steel means that the steel alloy used to make it consisted of 18% chromium and 10% nickel.

Sometimes, you’ll see this labeled differently. 18/10 and 18/8 stainless steel is commonly referred to as Grade 304 (or Type 304) steel, and 18/0 stainless steel is sometimes referred to as Grade 430 (or Type 430) steel.

Here’s a cheat sheet to refer to when in doubt:

GradeSteel AlloyCompositionCharacteristics
Grade 30418/10 stainless steel18% chromium, 10% nickelHighest resistance to corrosion and rust,
Polished look and feel
Grade 30418/8 stainless steel18% chromium, 8% nickelMedium resistance to corrosion and rust
Grade 43018/0 stainless steel18% chromium, < 0.7% nickelLowest resistance to corrosion and rust
Grades of stainless steel used for making cookware

Which Grade of Stainless Steel Is Best?

18/10 stainless steel is the highest-grade stainless steel for making cookware. Compared to 18/8 and 18/0 stainless steel, it’s the most resistant to corrosion and rust and can therefore last the longest.

However, the high content of nickel makes the steel austenitic (weakly magnetized or completely non-magnetic). This means that, unless paired with another grade of steel, cooking vessels made only of 18/10 stainless steel won’t work on induction cooktops.

Pair that with the fact that stainless steel as a whole is a poor conductor of heat, and you start to understand why manufacturers add another, more conductive metal in a disc bottom or through cladding.

Disc-Bottomed vs. Clad Cookware

As versatile and long-lasting as stainless steel is, it usually needs to be paired with another metal to make great cookware.

Stainless steel is notoriously bad at conducting heat. Pans and pots made solely of it take a long time to heat up and are prone to having plenty of cold spots, so they don’t really give you a good cooking experience.

To counter that, manufacturers of stainless steel cookware like to add another metal, like copper or aluminum, to their cooking vessels. This is understandable when you consider that copper conducts heat 29 times better than stainless steel, and aluminum is 16.5 times better (via Engineering Toolbox).

There are two ways to achieve this. Some manufacturers add the second metal as a disc attached to the bottom of their cookware pieces (known as “disc-bottomed cookware”). Others “sandwich” multiple layers of metal together to create clad cookware (known as “clad cookware” or “fully clad cookware”).

Clad vs. disc-bottomed cookware
Clad vs. disc-bottomed cookware

Disc-bottomed pans and pots are more affordable, but they don’t heat as evenly as their clad counterparts.

Tri-Ply, Five-Ply, Seven-Ply Stainless Steel

If clad cookware consists of three layers of metal, it’s called tri-ply. Respectively, if it consists of five or seven layers of metal, it’s called five-ply and seven-ply.

Typically, the bottom layer is made of magnetized steel to make the pan or pot induction-compatible, the core layer is made of aluminum and/or copper, and the cooking surface layer is made of 18/10 stainless steel.

More layers make for denser, heavier, and more conductive cookware. But its improved performance comes at a steeper price tag.

Personally, I’ve found tri-ply cookware with an aluminum core, such as the All Clad D3 12-inch skillet, to offer the best price/performance ratio for daily cooking in your home kitchen.

Putting It All Together

So, what do we make of all this?

The best stainless steel frying pans and pots are made of clad stainless steel with a tri-ply construction that consists of a magnetized exterior, aluminum core, and 18/10 stainless steel interior.

Cooking vessels that fit this description heat fast and are capable of distributing that heat evenly enough for your home cooking needs. You could always get ones with a copper core or more layers of metal (five-ply or seven-ply), but they’ll come at a much higher price that’s not always justified.

For what else to look for (size, handle, shape), check out my guide to buying a frying pan.

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